Done! Added a start screen with:
- Animated mining icons (⛏️💎🪨) that bounce
- Large "MINING GAME" title with glowing gold effect
- "Dig Deep, Strike Gold" subtitle
- Big "START" button that transitions to the game when clicked

**Next Ideas:**
1. **Save Progress** - Add localStorage to save gold, depth, and upgrades between sessions
2. **Boss Blocks** - Add rare mega blocks that require multiple hits and give massive rewards

**Ready to level up your game? Pick one and let's build it!**